Unless you want really high level trackers, you will have no real problem. If you can commit to seeding everything for at least 2-4 weeks 24/7, leave your pc on overnight, you can even get fantastic ratios with your private connection. At the entry level like IPT/TL, the only people who have ratio problems are people who download 50+ GB in their first week on a new tracker without paying attention, or those who try and HNR or underseed.

There is an exception however. In an environment where most other users are using seedboxes, it can be hard. I have found it is much easier to gain ratio by cross-seeding on high level trackers - you just hunt for torrents available where you have good ratio, and point the new tracker to the files. As long as you are patient and don't expect to immediately download huge amounts, you don't really need a seedbox.

Get a seedbox IF any of the following apply:
-You have a huge desire to boost your ratio
-You want to put less time into managing your ratio
-You want to quickly build a massive library of torrented files, and have tons of storage.